Weight Talk: Fitness, Health and Society

What’s a normal amount of percent change in body weight between winter and summer for everyone? It depends of course on how active/outside you are. I haven’t been outside much these past few years so I almost never get a change with the seasons.

As I understand it, the current medical consensus is that fat protects muscle, and has health benefits when it is in moderation, but increases risks for bad outcomes when in excess. And muscle weighs more than fat, and aside from heart disease, generally protects against death of all causes. If muscle is generally good, and fat is good in moderation, why do we still popularly conflate skinniness as healthiness?